Gold Alloys by Volume

Percentage by Weight v. Percentage by Volume

The Difference is Surprising

Gold alloys are always calculated by weight. For example 18 carat gold must contain at least 18 parts gold out of 24 parts total (75%). The proportions by volume can show a startling difference.
The graphic on the right shows the proportions by volume of gold, silver, copper and zinc in typical 18 carat and 9 carat yellow gold alloys.

9 Carat Only Contains 22% Gold!

As you can see, 9 carat yellow gold contains only 22% gold by volume. Consumers who saw gold alloys being mixed would only want to buy 18 or higher alloys. Indeed the more you know about all the qualities of gold alloys, the more you would only accept 18 carat or better.

The following tables show the approximate percentages by weight and by volume of some typical common gold alloys.

Percentages by Weight
Alloy Gold Silver Copper Zinc Nickel Palladium
9 Yellow 37.5 10 45 7.5 - -
9 White 37.8 0 40 10.4 11.8 -
14 Yellow 58.5 4 31.2 6.3 - -
14 White 58.5 0.5 27 7 7 -
18 Yellow 75 16 9 - - -
18 White 75 4 4 - - 17
22 Yellow 91.7 5.5 2.8 - - -
Percentages by Volume
Alloy Gold Silver Copper Zinc Nickel Palladium
9 Yellow 22 11 56 12 - -
9 White 21 0 48 16 14 -
14 Yellow 39 5 45 11 - -
14 White 39 1 38 12 10 -
18 Yellow 61 24 16 - - -
18 White 63 6 7 - - 23
22 Yellow 84 5 10 - - -

Notes:
Since we published the above information, nickel has been all but discontinued in jewellery use, therefore the formulations used in most white gold alloys have changed to eliminate nickel, and replace it with other metals. In higher carats such as eighteen, this would usually be palladium.

24 Carat